This invention relates generally to aircraft refueling and, more specifically, to uninhabited airborne vehicle refueling.
Uninhabited airborne vehicles (UAVs) are becoming widely used by the U.S. Navy and Air Force. Current UAV applications include surveillance, ground attack, and air interdiction. However, further expansion of UAV applications is hindered because, unlike piloted aircraft, they cannot be refueled during flight. Consequently, UAVs cannot perform applications requiring long ranges, such as deep strike interdiction, or long duration surveillance. UAVs also cannot be transported under their own power to remote locations, such as across oceans, because of their range limitations. Instead, UAVs must be flown across oceans in transport aircraft, which is expensive and ties up valuable resources needed for transporting other equipment. Because of these reasons, there exists a need to refuel UAVs in-flight. Because no UAV in-flight refueling system is currently known to exist, there is an unmet need in the art for a UAV in-flight refueling system.
The present invention provides automated air refueling (AAR) of uninhabited airborne vehicles (UAVs). According to an embodiment of the invention, a UAV AAR system includes any combination of a positioning system component, an air collision avoidance system (ACAS) component, a voice processing component, an image processing component, a flight controller, a wireless data link, refueling components, and a ground operation station. The voice processing component may be replaced by a wireless voice link to a human operator at the ground operation station using, such as, but not limited to, a satellite communications link. The positioning system component determines the absolute (longitude, latitude, altitude) location of the UAV. A similar system on the tanker determines the absolute position of the tanker, which is transmitted to the UAV over the wireless data link. The absolute position of the UAV and tanker is provided to the flight controller, which determines the relative position (azimuth, elevation, range) of the UAV relative to the tanker, and generates navigation instructions to guide the UAV into the proper position relative to the tanker such that the tanker can connect with the UAV to transfer fuel. The ACAS component also receives the absolute positions of the UAV, as well as the tanker and any other aircraft around the UAV via the wireless data link. The ACAS component also computes the relative position of the UAV relative to the tanker and other aircraft in the vicinity. The ACAS component uses that information to allow the UAV to avoid collisions with the tanker or other aircraft in the vicinity of the UAV. In the event the UAV is headed towards a collision with another aircraft, the ACAS component generates navigation instructions based on the relative position information, and sends the generated navigation instructions to the flight controller to safely fly the UAV away from the collision.
The voice processing component receives voice instructions over a voice communications channel, analyzes the received voice instructions, transmits a response according to autonomous analysis, generates navigation instructions according to the analysis, and sends the generated navigation instructions to the flight controller. The voice processing component transmits a response based on the sensed one or more conditions of the refueling components.
As an alternative, the voice processing component is replaced by a wireless voice link to a human operator at the ground operation station. For the purposes of simplification, the present invention assumes that voice processing component is used in the refueling operation, although either approach is included in this application.
The image processing component includes one or more digital cameras for generating one or more digital images, a memory, and an image processor. The image processor compares the generated one or more digital images to one or more comparable images stored in the image processing component""s memory to determine the position of the UAV relative to the tanker. The relative position information is sent to the flight controller, which compares the relative position information with that generated from the data sent by the positioning system. If the two relative position calculations are consistent, the flight controller generates navigation instructions to guide the UAV into position for refueling.
Should either the image processing component or the positioning component fail during the refueling operation, the refueling can be completed using other components. When both components are operational, they provide a safety check against errors or failures in either system. Embodiments of this invention using only one of these components are covered in this invention.